The worst of fish handling I witness is from cluless pleasure anglers who have no idea about how to deal with the fish thery catch. As a "match" angler I would say that 99% of my fish are returned to the water, safely, within ten seconds of being landed regardless of size. My biggest fish, an 18-6 carp was unhooked in my lap and back in the water within seconds. No need for a mat or the ground.
But I witness pleasure anglers regularly doing the following.
Net the fish and walk back from the bank before laying the fish on the ground.
Walk back to their box and search for a disgorger.
Then take sometimes minutes to unhook the fish.
Walk back to the bank with rod & line before returning to the fish.
Walk down the bank with the fish to show their mate, then take a photo
Walk further down the bank to release the fish at an empty peg.
Often this process takes 3-5 minutes or more by which time I am gagging to shout at them across the lake. Even when weighing in fish are often out of the water less than a minute.
I don't like dropping fish into the water and will usually use the landing net, even with small fish. But having seen fish jump, of their own accord, free of the surface I cannot think that dropping them from a low height causes any issues.
As for emptying a keepnet, there is a recognised best practice way of doing it that most match anglers have mastered. Pleasure anglers still tumble fish the length of the net.
